A system for realizing positioning operations through speed feedback control using a speed profile is widely used in a printing medium conveying apparatus of an inkjet printer and other applications related to other technical fields. However, in a case where positioning operations are performed based on a speed profile, when deviations occur with respect to the speed profile, variations may be created with respect to the actual distance traveled. Also, a substantial deviation with respect to the speed profile may result in substantial undershoot and overshoot to thereby cause oscillation and instability in the positioning operations.
It is noted that motor drive controlling techniques using a speed profile are disclosed in Japanese Laid-Open Patent Publication No. 2001-224189, Japanese Laid-Open Patent Publication No. 2001-169584, and Japanese Laid-Open Patent Publication No. 2003-348878, for example.
In the case of controlling a motor through a motor controlling scheme using a speed profile, when the drive load of the motor is not considered upon driving the motor to achieve a certain target profile, the time required for the motor to reach a predetermined rotation speed may vary depending on the drive load of the motor. Specifically, when the drive load of the motor is relatively light, the motor may reach the predetermined rotation speed in a relatively short period of time; on the other hand, when the drive load of the motor is heavy, a relatively long period of time may be required for the motor to reach the predetermined rotation speed.